Get rid of unused forward declaration in view.h
Get rid of unused forward declaration in view.h

Spotted by @zaowen:
https://github.com/newsboat/newsboat/pull/301#discussion_r223217120

der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat